In the hydrocarbon recovery industry boreholes are drilled to access hydrocarbon bearing formations for the purpose of extracting target fluids be the fluid gas, oil or a combination of fluids. While traditionally boreholes were drilled substantially vertically and therefore orientation of a bottom hole assembly could be relatively accurately tracked by tracking the orientation of the string at the surface, orientation in highly deviated or horizontal wells that are more common today is difficult and accuracy is limited. This is due in part to the frictional factors encountered as a string of several thousand feet is driven into the low side borehole wall. Because it is difficult to measure the friction all the way up the string, it is difficult to resolve the forces that act on the string and affect actual orientation downhole relative to apparent orientation at the surface.
Being able to accurately determine orientation in the downhole environment facilitates many operational interests. Therefore, the art is always receptive to new methods and apparatus that improve or enable orientation in the downhole environment.